(30c) Innovative Mixing of Paper Chest with 6%-14% Consistency Saves Energy and Improves Quality

In the Pulp & Paper industry stock chests with partial mixing and recirculation loops are used for blending and to reduce the magnitude of consistency fluctuations. Minimizing these fluctuations will provide final sheet properties with smoother surfaces, more uniform consistency and improved sheet strength. At the present time stock chests are only partially mixed with side entry mixers. Maximum consistency is limited to 6.5% due to mixing limitations. This paper discusses alternatives for minimizing these limitations by mixing the entire volume of the stock chest. This was not considered in the past due to prohibitive costs and lack of suitable mixing technology. With the proper application of new impeller technologies to achieve multiple areas of zonal mixing, the entire volume of the paper chest can now be uniformly mixed with only 50% of power required by traditional side entry mixers. This technology allows for the total material movement and uniform mixing of paper pulp up to 14% consistency.